1. Field of the Invention
The invention relates to novel aromatic polyester polycarbonate polyols, and more particularly relates to novel aromatic polyester polycarbonates made from alkylene carbonates or alkylene oxides and carbon dioxide reacted with residues from the manufacture of polyethylene terephthalate.
2. Description of Other Relevant Compounds in the Field
Polyurethane polymers and polyisocyanurate polymers such as those in rigid and flexible foams are well known in the art. The latter type of polymers are by utilizing a polyisocyanurate group formation catalyst to promote formation of both isocyanurate linkages and urethane linkages to produce urethane-modified polyisocyanurate polymers.
Both polyesters and polycarbonates have been used in the preparation of polyurethane polymers. Materials of this type are used to prepare both polyurethane and polyisocyanurate flexible and rigid foams as well as semi-flexible and semi-rigid foams. Polycarbonates may be made by reacting a glycol with a carbonate ester in the presence of a zinc borate-alkali earth metal oxide catalyst system as revealed in U.S. Pat. No. 3,133,113. Various techniques for preparing high molecular weight polycarbonates by reacting dihydric initiators with alkylene oxides and carbon dioxide are taught by U.S. Pat. Nos. 3,248,414; 3,248,415 and 3,248,416.
Polycarbonates have also found utility in coating and laminate form. U.S. Pat. No. 3,764,457 teaches laminates for use as automobile windshields comprising a polycarbonate urethane and one or more sheets of glass. The urethane is formed from an aliphatic polycarbonate, a cycloaliphatic diisocyanate and a monomeric aliphatic diol. Similar laminates employing hydroxyl-terminated polycarbonates are described in German Offenlegungschrifft No. 2,258,131 cited in Chemical Abstracts 82:58865v, 1975.
U.S. Pat. No. 3,758,443 describes the preparation of polyurethane elastomers by reacting polyester polyol polycarbonates, having a molecular weight of 800 to 2,500, with diisocyanates and low molecular weight polyhydric compounds having molecular weights lower than 400. Thermoplastic carbonate-modified co-polyesters for the injection molding process were made by the reaction of aromatic dicarboxylic acids or other esters of dihydric alcohols which have carbonic and ester groupings and hydroxyalkyl end groups according to U.S. Pat. No. 4,041,018.
U.S. Pat. No. 4,072,704 reveals that multiblock coupled polyalkylene glycol co-polymer surfactants may be prepared from individual blocks of polymers and co-polymers by the reaction of these with bifunctional compounds to form polycarbonate esters and polyformates. Further, polyester polycarbonates may be prepared by the reaction of cyclic organic anhydrides, alkylene oxides, carbon dioxide and polyhydric compounds as discussed in U.S. Pat. No. 4,267,120. These latter polycarbonates are shown to be useful for the preparation of polyisocyanurate foams.
While many of the polycarbonates described work well, it is always an objective to make these polycarbonates as cheaply as possible.